I believe it is more nuanced. Full disclosure: before moving to UK I worked for seven (7) years in a remote-first company. And while it is certainly
possible to run with a fully distributed, remote-only organisation, not every company can do that. The company would have to have been built, from day zero, to not merely "support" remote working but to fully endorse it. Starting from the founders.
When the plague hit, I was one of the few who knew how to transition from office to remote without a glitch - because I had the experience for how to do it. I honestly believe that fully remote can work only for a select few businesses, but mostly remote is perfectly doable for vast majority of tech and tech-adjacent companies.
To start, remote work self-selects for two types of people. Seniors, who already know how to work independently and productively - and the reasonably well-off who have the space and can afford to dedicate a physically separate study as their office. The overlap between the two is significant.
Several things are fundamentally more challenging in a fully remote setting. Such as...
1: Training and/or onboarding juniors. People entering the industry need constant supervision and near-synchronous assistance for a prolonged period of time. The first two years of your career you are clueless. Yes, you too, a HN reader. We ALL were! Training juniors takes time, skill, attention and - let's be honest - a personal touch. Doing that remotely is possible, but a lot harder. And only really possible in a company where everything has been built, from the ground up, to assume remote-first for everybody.
2: Active brainstorming. Bouncing ideas rapidly off of each other depends on establishing a rhythm where any communication delays are detrimental and can crash the cycle at any time. Having to devote brain cycles to communication delays and/or equipment detracts your attention.
3: Mob debugging. Very few things are more effective at complex root-cause analysis than having two or three people cluster around the same set of desktops, with enough large monitors to pull up new dashboards on a whim, and a whiteboard or three ready for quick scribbles and ad-hoc diagrams.
4: Random encounters. The US term is for some reason "watercooler effect", but in my experience "not at the office"-effect would be more accurate. If your culture manages to encourage people to take a walk outside the office setting, a small but meaningful fraction of those end up with valuable insights and outsized productivity boosts. Getting away from the physical office, while discussing things with coworkers, is an essential aspect.
5: Cultural cohesion. Maintaining a good company culture is tricky when most communication happens without leadership having any clue of it taking place at all. The only solution I can think of is solid trust.
Replicating or reproducing any of the above in a remote-only setting is incredibly hard. However - remote work has enormous benefits that don't necessarily show up directly. Such as:
Ten-second commutes. The ability for a remote worker to effectively flip from at-home mental state to at-work mental state, without having to endure commute is an incredible advantage.
Disturbance shutdowns. At remote work we can completely block off coworkers (or managers) from disrupting the flow. Just remember to also set your phone to silent.
"Friendly face effect". When your mostly-remote workforce does meet in person, they tend to spend time talking about things they have had simmering at the back of their minds. Stuff that has takenl iterally weeks to form. And they are for most parts happy to see each other. Compare that to office work, where seeing the same faces day after day gets dreary, really quick.
Encouraging async communications. When you have to properly think through what you want to convey, and actually take time to do it right, email chains can become quite fruitful[0]. Sure, the latency of communication may be slower, but the S/N ratio for non-combative topics tends to be high. (For combative topics, nothing helps. Best way to resolve them is to put the people involved in a cage and let them pummel each other to different shades of blue.)
For all of the reasons above, I believe that for most companies the best approach in the long run will be "mostly-remote". Have people meet in person for couple of days every couple of weeks, so that they can get all the synchronous activities done in one batch, and then let them disperse back to their home offices to focus on their real product-oriented work.
Onboarding juniors and non-senior new hires is still going to be tough. For companies that thrive on hiring newgrads, it's unlikely they could ever embrace remote work for real.
One of the unexpected downsides of mostly-remote is that a company going down that route is incentivised to have location based salaries. This works, mostly, when their staff live reasonably near large cities. But by incentivising their workforce to relocate to lower CoL areas during employment, they are actually also encouraging social isolation. I saw this first hand - and it's not healthy.
0: Writing a good email takes time. You may have to spend an hour on it, just to ensure that readership can not easily misunderstand the message you want to convey.